D7610: rust-threads: force Rayon to respect the worker count in config

[Alphare (Raphaël Gomès)]

Alphare created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  As per the inline comment, this is a workaround because Rust code does not yet
  know how to read config files.

REPOSITORY
  rHG Mercurial

BRANCH
  stable

REVISION DETAIL
  https://phab.mercurial-scm.org/D7610

AFFECTED FILES
  mercurial/dirstate.py

CHANGE DETAILS

diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -1116,6 +1116,17 @@
             use_rust = False
 
         if use_rust:
+            # Force Rayon (Rust parallelism library) to respect the number of
+            # workers. This is a temporary workaround until Rust code knows
+            # how to read the config file.
+            numcpus = self._ui.configint("worker", "numcpus")
+            if numcpus is not None:
+                encoding.environ.setdefault(b'RAYON_NUM_THREADS', b'%d' % numcpus)
+
+            workers_enabled = self._ui.configbool("worker", "enabled", True)
+            if not workers_enabled:
+                encoding.environ[b"RAYON_NUM_THREADS"] = b"1"
+
             (
                 lookup,
                 modified,



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